Photoflash circuit



y 1956 s. D. EILENBERGER 2,755,416

PHOTOFLASH CIRCUIT Filed April 10, 1953 Extension LumpIJI Extension Lamp11 Extension Lump I INVENTOR. Stanley D. Eilenberger A TTOR/VE Y UnitedStates Patent Ofliee Patented July 17, 1956 PHOTOFLASH CIRCUIT StanleyD. Eilenberger, Kittredge, Colo., assignor, by

mesne assignments, to Minneapolis-Honeywell Regulator Company,Minneapolis, Minn., a corporation of Delaware Application April 10,1953, Serial No. 347,998

'3 Claims. (Cl. 315192)' This invention relates to improvements inphotoflash equipment circuits and more particularly to those which haveextension lamps or sidelights for use with a master lamp or flash gun ofthe battery capacitor type. More specifically, the invention relates toimprovements in the type of circuits referred to where the extensionlamps or sidelights are to be wired in series. Considerable difficultyhas been experienced with present commercial units of this type becauseit has been the practice to use either self-closing mechanical contacts,which are inherently unreliable and introduce undesirable resistance inthe circuit, or to use a so-called shorting plug at the terminatinglamp.

An object of this invention is to provide a circuit for use inphotoflash extension lamps or sidelights which will allow any number ofunits to be wired in series without the use of special shorting plugs orself-closing contacts.

Referring now to the single figure, the part of the circuit left of theline AA represents, by way of example only, the stored energy circuitfor the master unit or flash gun where 1 is the primary battery, usuallyon the order of 22 /2 to 30 volts, 3 is the energy storage capacitor,the value of which depends upon the voltage of battery 1 and the numberof flash bulbs it is desired to fire at once where a nominal value wouldbe on the order of 300 to 500 microfarads. In series with the batteryand capacitor is a series charging resistor 2, the value of which isnoncritical and a nominal value may be on the order of 1,000 to 3,000ohms. An operating switch is indicated at 4 which is of the single-pole,single-throw, normally open type. The master lamp is indicated at M andit is in the discharge circuit for the capacitor which will becontrolled by the switch 4. The outlet 5 is provided in the discharge oroperating circuit for connecting the extension or side lamps.

The extension or side lamps are shown by the part of the circuit to theright of line AA and are connected to the stored energy circuit by plug7 which will be in serted into outlet 5, said plug 7 having a cord 6which may be of any desired length, and on its other end is a plug 8 forconnection to the first extension lamp.

In the figure there is shown, by way of example, three extension lampsindicated as I, II and III. There may be fewer or more as desired. Eachextension lamp hook will be alike and, as shown, there are seriesoutlets 9 and 10 and a terminal or end outlet 11. The series outlets 9and 10 have one each of their terminals directly connected together. Thetwo remaining terminals are connected together through the flash lamp 12and connected parallel therewith is the terminal outlet 11.

In connecting the extension lamps together, the plug 8 on the cord 6coming from the outlet 5 of the stored energy circuit will be connectedinto the outlet 9 of the first extension lamp I. The second extensionlamp II will be connected to the first extension lamp I by a suitablecord 13 having end plugs 14 and 15, with plug 14 being connected intoseries outlet 10 of extension lamp I and plug 15 connected into seriesoutlet 9 of extension lamp 11. Extension lamp III, which is the terminallamp, will be connected to extension lamp II by a suitable cord 16having end plugs 17 and 18. Plug 17 will be connected into series outlet10 of extension lamp II and the plug 18 will be connected into the endor terminal outlet 11 of this terminal extension lamp III.

With the above manner of connection it will be seen that the threeextension lamps are now in series circuit with the energy storagecircuit. If only one extension lamp is desired, then plug 8 will beinserted into the end or terminal outlet 11 of extension lamp I. If onlytwo extension lamps are desired, then plug 15 of cord 13 will beconnected into the end or terminal outlet 11 of extension lamp II.Regardless of how many extension lamps are desired, all except the lastwill be connected together by their series outlets and this last will beconnected to the next to last by its end or terminal outlet 11.

The number of extension lamps that can be connected together will dependon the voltage of battery 1. The length of the connecting cords willalso have some eifect on the number of lamps that can be connectedtogether as the cords have appreciable resistance, although such is notcritical. Lengths of cords up to feet have been used with five or sixlamps in series.

In commercial use of the extension lamp hookups, the outlets of eachwill be marked with suitable indicia so one will readily know into whichoutlet a plug is to be inserted. For example, a suitable marking couldbe the word series for the outlets 9 and 10, and the word end orterminal for the outlet 11.

With my improxed extension lamp hookup it is readily seen that noself-closing contacts or special terminating plug are required. Theconnecting of extension lamps in series can be quickly and easilyaccomplished and with no uncertainty involved.

It is not intended that the scope of my invention be limited, except inaccordance with the appended claims.

What is claimed is:

l. A photoflash extension lamp unit for connection with a master flashcircuit having a source of power, a main flash lamp and a switch forconnecting said main flash lamp to said source of power, said extensionlamp unit being adapted to be connected directly to said master flashcircuit or to another such extension lamp unit to form a series of lampsall connected to said source of power, said extension lamp unitcomprising a pair of two terminal outlets having no electricalconnection directly between the terminals of each outlet but having oneterminal of one outlet connected to the corresponding terminal of theother outlet, an extension flash lamp connected between thecorresponding other terminals of said outlets, and a third outlet havingtwo terminals connected across said lamp, the terminals of said thirdoutlet serving as the input terminals to the flash lamp when the lampunit is the final unit in a series and the terminals of said pair ofoutlet serving as the in and out terminals when said extension lamp unitis not the final unit in the series.

2. In a photoflash arrangement: a master flash circuit including asource of power, a main flash lamp, a switch for connecting said mainflash lamp to said source of power and an outlet in series with saidswitch and said source of power; at least three extension lamp unitsconnected to said master flash circuit to be operated simultaneouslywith said main lamp, each of said extension lamp units comprising a pairof two terminal outlets having no electrical connection directly betweenthe terminals of each outlet but having one terminal of one outletconnected to the corresponding terminal of the other outlet, anextension flash lamp connected between the corresponding other terminalsof said Outlets, and a third outlet having two terminals connectedacross said lamp; and electrical connecting cords having end plugs conneting the units so that the extension lamps are connected in series withsaid source of power and said switch, one cord extending between saidoutlet of said master flash circuit and one of the pairs of outlets ofthe first extension unit in the series, another cord extending be tweencomplementary outlets of two extension units, and a further cordextending between one of said pairs of outlets of the next to the lastunit in the series and the third outlet of the last unit in the series.

3. In a photoflash arrangement: a master flash circuit including asource of power, a main flash lamp, a switch for connecting said mainflash lamp to said source of power and an outlet in series with saidswitch and said source of power; at least two extension lamp unitsconnected to said master flash circuit to be operated simultaneouslywith said main lamp, each of said extension lamp units comprising a pairof two terminal outlets having no electrical connection directly betweenthe terminals of each outlet but having one terminal of one outletconnected to the corresponding terminal of the other outlet, anextension flash lamp connected between the corre sponding otherterminals of said outlets, and a third outlet having two terminalsconnected across said lamp; and electrical connecting cords having endplugs connecting the units so that the extension lamps are connected inseries with said source of power and said switch, one cord extendingbetween said outlet of said master ilash circuit and one of the pairs ofoutlets of the first cxtcm sion unit in the series, and a further cordextending between one of said pairs of outlets of the next to the lastunit in the series and the third outlet of the last unit in the series.

References Cited in the file of this patent UNITED STATES PATENTS2,395,600 Weisglass Feb. 26, 194% 2,638,764 Schwartz et al. May 19, 19532,646,672 Fairbank July 28, 195")

